THE HAND (Fam, 2003)

The hand is the chief sensory organ of touch and is uniquely adapted for grasping. The radial side of the hand performs a pinch grip between the fingers and thumb, and the ulnar side performs a power grip between the fingers and palm. The bones of the hand can be divided into a central, fixed unit for stability and three mobile units for dexterity and power. The fixed unit consists of the eight carpal bones tightly bound to the second and third metacarpals (Figure 4-1). The three mobile units projecting from the fixed unit are:

FIGURE 4-1 BONES AND JOINTS OF THE WRIST AND HAND.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

The axis of the wrist and hand is an extension of the longitudinal axis of the radius and the third metacarpal, with the wrist in the neutral position. Because of the changing position of the wrist and hand with forearm pronation and supination, it is best to describe locations in the wrist awnd hand as volar (palmar), dorsal, radial, and ulnar rather than anterior, posterior, lateral, and medial. The hand has two arches: a longitudinal arch, in the mid palm from wrist to fingers, and a transverse arch across the mid palm. In the resting position, the fingers are normally slightly flexed at the metacarpophalangeal (MCP) and interphalangeal (IP) joints; this is referred to as the resting flexion cascade of the fingers.

WRIST JOINT

The radiocarpal joint is the proximal articulation of the wrist and is an ellipsoid joint between the distal radius and articular disk proximally and the scaphoid, lunate, and triquetrum distally (see Figure 4-1). The capsule is strengthened by the radiocarpal (dorsal and volar) ligaments. The articular disk, or triangular fibrocartilage of the wrist, joins the radius to the ulna. Its base is attached to the ulnar border of the distal radius, and its apex is attached to the root of the ulnar styloid process. The synovial cavity of the distal radioulnar joint is L-shaped and extends distally beneath the triangular fibrocartilage but is usually separated from the radiocarpal joint.

The radiocarpal, midcarpal distal radioulnar, and CMC joints do not communicate under normal circumstances. The presence of any communication, tested by wrist arthrography or MR arthrograms, implies torn ligaments or a torn capsule between them. The midcarpal joint is in continuity with the intercarpal joints except for the pisotriquetral articulation, which communicates with the radiocarpal joint (see Figure 4-1).

The carpal bones form a volar concave arch or carpal tunnel, with the pisiform and hook of the hamate on the ulnar side and the scaphoid tubercle and the crest of the trapezium on the radial side. The four bony prominences are joined by the flexor retinaculum (transverse carpal ligament), which forms the roof of the carpal tunnel. The distal flexion crease of the wrist marks the proximal border of the retinaculum. The palmaris longus (absent in 10% to 15% of the population) partly inserts into the flexor retinaculum and partly fans out into the palm, forming the palmar aponeurosis (fascia). The aponeurosis broadens distally and divides into four digital slips that attach to the finger flexor tendon sheath, MCP joint capsules, and proximal phalanges. There is usually no digital slip to the thumb (Markison, 1987).

Twenty-four extrinsic tendons cross the wrist and provide a unique combination of power and dexterity to the hand. Each tendon is enclosed for part of its course in a tenosynovial sheath. A wrist or finger tendon sheath is lined by an inner or visceral synovial layer that adheres closely to the tendon and an outer or parietal synovium that covers the inside of the fibrous tendon sheath. The visceral and parietal synovial tubes are united longitudinally by the mesotendon, a synovial fold that transmits vessels and nerves to the tendon. The mesotendon may disappear partially in some tendon sheaths and may be represented by threads or vinculae.

The common flexor tendon sheath encloses the long flexor tendons of the fingers (Strauch, 1985) (flexor digitorum superficialis and flexor digitorum profundus) and extends from approximately 2.5 cm proximal to the wrist crease to the mid palm. It runs with the flexor pollicis longus tendon sheath and the median nerve through the carpal tunnel (Figure 4-2). The tendon sheath of the little finger is usually continuous with the common flexor sheath. The flexor pollicis longus tendon to the thumb runs through a separate tenosynovial sheath but may join the common flexor sheath. The flexor carpi radialis is invested in its own short tendon sheath as it crosses the volar aspect of the wrist between the split radial attachment of the flexor retinaculum. It is separated from the carpal tunnel by the deep portion of the transverse carpal ligament. The flexor retinaculum straps down the flexor tendons as they cross at the wrist. The ulnar nerve, artery, and vein cross over the retinaculum but are covered by a fibrous band, the superficial part of the transverse carpal ligament, to form the ulnar tunnel, or Guyon canal.

FIGURE 4-2 FLEXOR TENDONS AND TENDON SHEATHS OF THE WRIST AND FINGERS.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

On the dorsum of the wrist, the extensor tendons pass through six tenosynovial, fibro-osseous tunnels beneath the extensor retinaculum: 1) the abductor pollicis longus and extensor pollicis brevis (usually in a single sheath), which constitute the first, most radial extensor compartment; 2) the extensor carpi radialis longus and brevis; 3) the extensor pollicis longus; 4) the extensor digitorum communis and extensor indicis proprius; 5) the extensor digiti minimi; and 6) the extensor carpi ulnaris, the most ulnar extensor compartment (Figure 4-3). Each tenosynovial sheath extends about 2.5 cm proximally and distally from the retinaculum. The extensor retinaculum, by its deep attachments to the distal radius and ulna, binds down and prevents bowstringing of the extensor tendons as they cross the wrist. The anatomic snuffbox corresponds to the depression between the extensor pollicis longus tendon and the tendons of the abductor pollicis longus and extensor pollicis brevis.

FIGURE 4-3 EXTENSOR TENDONS AND TENDON SHEATHS OF THE WRIST.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

Movements of the wrist include flexion (in the volar direction), extension, ulnar deviation, radial deviation, and circumduction. The intercarpal joints, particularly the lunate-capitate joint, contribute to wrist extension and flexion. Prime wrist flexors are the flexor carpi radialis, flexor carpi ulnaris, and palmaris longus. The prime extensors are the extensor carpi radialis longus and brevis and extensor carpi ulnaris.

CARPOMETACARPAL JOINTS

The first CMC joint is a saddle-shaped, very mobile articulation between the trapezium and the base of the first metacarpal. It allows 40° to 50° of thumb flexion–extension parallel to the plane of the palm and 40° to 70° of adduction–abduction perpendicular to the plane of the palm. These movements are important in bringing the thumb in opposition with the fingers. The second and third CMC joints are relatively fixed, but the fourth and fifth are mobile, allowing the fourth and fifth metacarpals to flex forward (15° to 30°) toward the thumb during power grip.

METACARPOPHALANGEAL JOINTS

The metacarpophalangeal (MCP) joints are ellipsoid joints that lie about 1 cm distal to the knuckles (metacarpal heads; see Figure 4-1). Their capsule is strengthened by the radial and ulnar collateral ligaments on the sides and by the volar plate on the volar surface. Because of the cam shape of the metacarpal head, the collateral ligaments are loose in the neutral position, allowing radial and ulnar deviations, but become tight in the flexed position, preventing side-to-side motion, referred to as a sagittal cam effect. The deep transverse metacarpal ligament joins the volar plates of the second to fifth MCP joints. The MCP joint of the thumb is large and has two sesamoid bones overlying its volar surface.

When the long extensor tendon of the digit reaches the metacarpal head, it is joined by the tendons of the interossei and lumbricals and expands over the dorsum of the MCP joint and digit to form the extensor hood or extensor expansion (Figure 4-4). The expansion divides over the dorsum of the proximal phalanx into an intermediate slip, inserted principally into the base of the middle phalanx, and two collateral slips inserted into the base of the distal phalanx (von Schroeder, 1997).

FIGURE 4-4 TENDON INSERTIONS OF THE FINGER AND EXTENSOR DORSAL EXPANSION (HOOD).

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

The first MCP joint permits 50° to 70° flexion and 10° to 30° extension. Radial and ulnar deviations are limited to less than 10° to 20°. The other MCP joints allow 100° flexion, 10 to 20° extension, and 35° of radial and ulnar movement. The extensor pollicis brevis, extensor indicis proprius, extensor digitorum communis, and extensor digiti minimi extend the MCP joints (von Schroeder, 1993). The flexors are the flexor pollicis brevis, lumbricals, interossei, and flexor digiti minimi brevis, assisted by the long flexors. Radial and ulnar movements at the second to fifth MCP joints are a function of the intrinsic muscles.

INTERPHALANGEAL JOINTS

The proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints of the fingers and the IP joint of the thumb are hinge joints. Their capsules are strengthened by the collateral ligaments on the sides and by the volar plates on the volar surface, which serve to limit hyperextension, particularly at the PIP joints. Unlike the MCP joints, the radial and ulnar collateral ligaments remain taut in all positions, providing side-to-side stability throughout the range of movement.

The flexor tendon sheaths for the fingers enclose the tendons of the flexor digitorum superficialis and profundus to their insertions on the middle and distal phalanges, respectively. The sheaths extend from just proximal to the MCP joints to the bases of the distal phalanges (see Figure 4-2). The flexor sheath of the little finger is often continuous with the wrist common flexor tendon sheath. The thumb flexor pollicis longus tendon sheath extends proximally to the carpal tunnel. Segmental condensations, or annular pulleys, in the digital flexor sheaths prevent bowstringing of the tendons and are biomechanically critical for full digital flexion.

The PIP joints can hyperextend by 10° in young adults, and the joints allow 100° to 120° volar flexion. The DIP joints permit 50° to 80° volar flexion and 5° to 10° extension. The IP joint of the thumb allows 80° to 90° volar flexion and 20° to 35° extension. The flexor digitorum superficialis flexes the PIP joints, and the flexor digitorum profundus flexes the DIP joints of the fingers. The prime extensors are the interossei and the lumbrical muscles. The flexor pollicis longus flexes the IP joint of the thumb, and the extensor pollicis longus extends the joint.

INSPECTION

With the hands on the examining table, one makes a general assessment of age, inflammation, atrophy, deformity, and asymmetry. Age-related changes include prominent veins on the dorsum of the hand, mild atrophy of the intrinsic muscles, lentigines on the skin and osteoarthritic prominences at the CMC joint at the base of the thumb, and osteophytes at the DIP and PIP joints. Osteoarthritic changes are ubiquitous and eventually result in such enlargement of the small joints of the fingers and deformity (McMurtry, 1986).

Acute inflammation following trauma is characterized by regional swelling and erythema. In contrast, chronic inflammation has less swelling and erythema and is often associated with synovitis of the joints and/or tendons. Deformity of any or all joints occurs with all forms of arthritis, but the particular pattern of deformity can be characteristic of a specific type of arthritis and will aid in diagnosis. The deformity will mirror the patient’s functional limitations and will dictate treatment. Assessing the deformity, motion, and instability of each digit requires a systematic approach and thorough documentation. Detailed wrist palpation, including provocative testing for carpal instability, will allow the examiner to localize specific disorders.

ASSESSING SYNOVITIS OF THE JOINTS AND TENDONS

Chronic synovitis is best assessed on the dorsum of the hand and wrist, where the tendons and joints are close to the surface and have fewer constraining structures over them. Synovitis of the joints produces a diffuse swelling over the joint and is uniformly tense and sometimes warm to the touch (McMurtry, 1986). The PIP and DIP joints are palpated by compressing laterally and/or gently forcing the joint into hyperextension for tenderness (stress pain). Synovial thickening and effusion are assessed by the examiner using the thumbs and forefingers of both hands placed on opposite sides of the joint (Figure 4-5). An effusion can be detected by the balloon sign: compression of the joint by one hand produces ballooning, or a hydraulic lift, sensed by the other hand. Unlike PIP synovitis, dorsal knuckle pads produce a nontender thickening of the skin localized to the dorsal surface of the PIP joints. The thumb MCP joint can be assessed in the same way. Tenderness in the MCP joints of the second to fifth digits are assessed by placing the examiner’s thumb under the volar aspect of the proximal phalanx, the fingers on the dorsum of the hand, and stressing the joint into hyperextension. An effusion can be ballooned by compressing the flexed MCP joint from the dorsoradial side and palpating the fluctuance from the dorsoulnar side (Figure 4-6).

FIGURE 4-5 PALPATION OF THE PROXIMAL INTERPHALANGEAL JOINT.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

FIGURE 4-6 PALPATION OF THE METACARPOPHALANGEAL JOINT.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

Tenosynovial effusion of the extensor tendons is localized to the tendon sheath and may have an hourglass configuration as it expands on either side of the extensor retinaculum. When the fingers are actively extended, the distal margin of the swelling moves proximally and folds in, like a sheet being tucked under a mattress (tuck sign). The swelling may be more oval over the extensor carpi ulnaris. Chronic synovial effusions of the tendons may have a gel-like consistency with minimal erythema. Synovitis of the wrist is best appreciated by placement of the examiner’s thumbs side by side transversely across the carpus, just distal to the Lister tubercle. Pressure on the wrist by one thumb causes the other to be lifted by fluid or soft-tissue swelling.

Finger flexor tenosynovitis produces linear tenderness, volar swelling, thickening, nodules, and/or crepitus of the tendon sheath (sausage finger). Trigger fingers are tested by palpation for nodules, tenderness, clicking, or catching at each flexor A1 pulley at the distal palmar crease. Flexion contractures of the PIP or DIP joints of the fingers can be due to tendon or intrinsic muscle contractures. Relaxing these structures by flexing the MCP joints while attempting to extend the PIP or DIP joints will determine whether the contracture is articular or due to extrinsic structures.

DEFORMITY PATTERNS

Rheumatoid Arthritis (RA)

RA can result in deformity of any or all of the joints of the hand and wrist. Boutonnière’s deformity describes a finger with flexion of the PIP joint and hyperextension of the DIP joint (Figure 4-7A). A swan-neck deformity describes the appearance of a finger in which there is hyperextension of the PIP joint and flexion of the DIP joint (see Figure 4-7B). In swan-neck finger deformity, tightness and shortening of the intrinsic muscles (interossei and lumbricals) results in restriction of PIP flexion when the MCP joint is extended. Therefore, with the MCP joint extended, the range of PIP flexion is less than when the MCP joint is flexed (positive Bunnell test). Z-shaped deformity of the thumb is caused by flexion of the MCP joint and hyperextension of the IP joint (see Figure 4-7C). Z-shaped deformities, finger deformities, and MCP synovitis produce a diffuse swelling of the joint that may obscure the valleys between the knuckles. MCP joint deformities include ulnar drift, volar subluxation (often visible as a “step”), and flexion deformities. The extensor tendons subluxate into the valleys on the ulnar side of their respective digits.

FIGURE 4-7 DEFORMITIES OF THE FINGER AND THUMB.

A, Boutonnière’s deformity of the finger. B, swan-neck deformities of the fingers. C, Z-shaped deformities of the thumbs.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

Wrist deformities are common in RA and include volar subluxation of the carpus with a visible step opposite the radiocarpal joint, carpal collapse (loss of carpal height, the distance from distal radius to base of metacarpal, to less than half the length of the third metacarpal), and radial posturing (radial deviation) of the carpus. Chronic arthritis of the distal radioulnar joint results in instability and dorsal subluxation of the ulnar head with “piano key” movements on upward or downward pressure.

PALPATION OF THE WRIST: ASSESSING BONES, JOINTS, AND LIGAMENTS

The wrist is best examined in the “arm wrestling” position, with the patient’s elbow on the examining table and the hand up (Figure 4-8). In this position, motion in all directions is checked, all of the carpal bones can be palpated, and key ligaments can be assessed. The scaphoid (Beckenbaugh, 1984) is palpated at three points (Figure 4-9). First, the scaphoid tubercle is prominent on the volar aspect of the wrist proximal to the thenar eminence (Figure 4-9A). It becomes more prominent as the scaphoid flexes in the volar direction while the wrist is brought into radial deviation. The Watson maneuver (scaphoid shift) (Watson, 1988) tests the integrity of the scapholunate ligament (see Scapholunate Ligament, p. 39; Figure 4-19). Tenderness directly at the scaphoid tubercle may be due to a fracture of the tubercle or osteoarthritis at the scaphotrapeziotrapezoid (STT) joint. The second point to palpate the scaphoid is the anatomical snuffbox on the radial aspect of the wrist (Figure 4-9B). With the examiner’s fingertip in the snuffbox, ulnar deviation of the wrist will allow palpation of the scaphoid ridge in the waist of the bone. Tenderness here represents acute fracture (De Smet, 2002), fracture nonunion (pseudoarthrosis), or synovitis. The third place to examine the scaphoid and scapholunate region is between the third and forth compartments on the dorsum of the wrist and about 2 cm distal to the Lister tubercle (Figure 4-9C). This “soft spot” is also used for injecting the radiocarpal joint and as an arthroscopic portal. Palpations at this spot during wrist flexion will bring the proximal portion of the scaphoid under the examiner’s finger.

FIGURE 4-8 THE “ARM WRESTLING” POSITION for wrist examination.

The wrist is best examined in this position, with the patient’s elbow on the examining table and the hand up. This allows the patient to relax their hand and allows the examiner to easily maneuver the wrist, palpate all of the carpal bones, and test for stability.

FIGURE 4-9 THREE POINTS for PALPATING THE SCAPHOID.

A, The scaphoid tubercle (arrows) becomes more prominent as the scaphoid flexes during wrist movement into radial deviation. B, The scaphoid waist is palpable in the anatomical snuffbox (circle), between the extensor tendons of the first compartment and the epl; the scaphoid ridge becomes more prominent here with ulnar deviation of the wrist. C, The proximal portion of the scaphoid is palpable in the soft spot (circle) between the tendons of the third and fourth (3/4) compartment, just distal to the Lister tubercle.

The lunate is directly distal to the distal radioulnar joint, below the tendons of the fourth and fifth compartments (Figure 4-10). It is not readily distinguishable, but like the proximal scaphoid, the lunate is palpable as the wrist is brought into full flexion. Tenderness here is associated with Kienböck osteonecrosis of the lunate.

FIGURE 4-10 THE LUNATE (CIRCLE) IS PALPATED JUST BEYOND THE DISTAL RADIOULNAR JOINT.

The dorsal prominence of the triquetrum is readily palpable distal to the ulnar head (Figure 4-11). It becomes more prominent in radial deviation. Tenderness may be associated with a shear fracture of the prominence resulting from a fall. A smaller prominence may be palpable on the ulnar side of the triquetrum. Volar to the triquetrum is the pisiform at the base of the hypothenar eminence (Figure 4-12); a sesamoid bone in the flexor carpi ulnaris tendon, it is slightly mobile in a radial-ulnar direction. Osteoarthritis may develop at the synovial joint between the pisiform and triquetrum and is characterized by pain on direct palpation of the joint at the ulnar side of the hand and by pushing the pisiform against the triquetrum while moving it side to side.

FIGURE 4-11 THE DORSAL PROMINENCE OF THE TRIQUETRUM (ARROW).

This point is readily palpable distal to the head of the ulna. it becomes more prominent with radial deviation.

FIGURE 4-12 THE PISIFORM (ARROW).

Located at the base of the hypothenar eminence, it can be mobilized a few millimeters in the radial and ulnar direction.

Approximately 2 cm distal and radial to the pisiform is the hook of the hamate (Figure 4-13). It is a vaguely defined prominence on palpation and may be slightly tender in normal individuals. It is significantly tender following a fracture or fracture nonunion of the hook. The dorsum of the hamate is palpable as a flat region just distal to the dorsal triquetral prominence (Figure 4-14). The fifth carpometacarpal (CMC) joint is assessed by palpating directly over the joint as the metacarpal is flexed and extended. Tenderness may represent post-traumatic or de novo osteoarthritis at the joint.

FIGURE 4-13 THE HOOK OF THE HAMATE.

A vague prominence just distal and radial from the pisiform (p).

FIGURE 4-14 THE DORSUM OF THE HAMATE.

A flat region (triangle) just distal to the dorsal triquetral prominence.

The dorsum of the capitate is palpable at its waist (Figure 4-15). This is a soft spot at the base of the third metacarpal. It is located approximately 1 cm distal and ulnar to the dorsal soft spot, where the scaphoid was palpated just beyond the Lister tubercle.

FIGURE 4-15 THE DORSUM OF THE CAPITATE.

Palpable as a soft spot at the base of the third metacarpal (black arrow) and distal to the soft spot of the proximal scaphoid (white arrow).

The dorsal base of the index metacarpal flares, and this bony prominence can increase with age and osteoarthritis, in which case it is referred to as a carpal boss (Figure 4-16). The trapezoid bone is located proximal to the prominent base of the second metacarpal and under the extensor carpi radialis longus tendon that inserts into the metacarpal.

FIGURE 4-16 THE BASE OF THE SECOND METACARPAL.

This is felt as a prominence (black arrow). It becomes increased in size with age and arthritis. The second CMC joint and trapezoid bone are proximal to the metacarpal base (white arrow).

At the base of the thumb metacarpal, and with rotational movement of the metacarpal, the CMC joint and the trapezium are palpated (Figure 4-17). This is best assessed by pinching the joint region on either side of the tendons of the first compartment with the pulps of the examiner’s index finger and thumb. Osteoarthritis is particularly common at this joint, especially in women, and can be assessed by axially loading the metacarpal and translocating or “grinding” the CMC joint to look for pain and crepitus. “Squaring” of the joint is noted on inspection of patients with moderate to severe osteoarthritis.

FIGURE 4-17 FIRST CMC JOINT.

The joint is best palpated by using the pulps of the thumb in index finger, while the metacarpal is put through a range of motion with axial loading and attempted subluxation.

The distal radioulnar joint (DRUJ) is palpable as a sulcus on the radial side of the ulnar head on the dorsum of the wrist. It is a forearm joint through which pronation and supination occur. This arc of motion is tested with the elbow locked on the examination table, or with the elbow at the patient’s side, to prevent shoulder contribution to the motion. Tenderness at the joint is most commonly due to post-traumatic osteoarthritis due to fracture, incongruence associated with a distal radius fracture or malunion; de novo osteoarthritis and inflammatory arthritis, especially rheumatoid, occur here as well.

The sulcus between the ulnar head and the dorsal prominence of the triquetrum is the location of the triangular fibrocartilage complex (TFCC; Figure 4-18). The central disk component supports the carpus, whereas the fibrous ligaments stabilize the DRUJ. Tenderness at the TFCC implies a degenerative or traumatic tear. Degenerative changes commonly occur with age and in individuals who have an ulnar length that exceeds the radial length, known as ulnar-positive variance. Acute tears can occur following a fall. Tenderness can also be tested on the volar aspect of the TFCC, just proximal to the pisiform and under the flexor carpi ulnaris (FCU) tendon. In this region, the volar ulnocarpal ligaments contribute to the TFCC structure. Finally, TFCC tenderness can be noted directly on the ulnar aspect of the wrist beyond the head of the ulna and between the FCU and extensor carpi ulnaris (ECU) tendons. This region, sometimes referred to as the mini snuffbox, also contains the ulnar styloid, which can become tender following fracture or nonunion. Stability of the DRUJ, as determined primarily by the integrity of the TFCC, is best tested by stabilizing the distal radius and carpus with one hand, on the radial aspect of the wrist, and translating the neck of the ulna in the volar and dorsal direction with the other hand. Pain and relative motion between the ulnar head and the radius should be assessed and compared to the other side, because the joint normally subluxes a few millimeters. The joint should be completely stable with the wrist in full pronation and full supination. The test can also be performed by looking for the “piano key” volar or dorsal shift of the head of the ulna as the patient pushes the hand down on a table with an outstretched arm or pushes the hand up against resistance.

FIGURE 4-18 THE TRIANGULAR FIBROCARTILAGE COMPLEX.

The TFCC is palpated with the tip or side of the examiner’s finger on the dorsum in the sulcus between the ulnar head and triquetrum (top arrow) distal to the ulnar head (bottom arrow). It can also be palpated proximal to the pisiform.

PROVOCATIVE CARPAL TESTING FOR INSTABILITY AND ARTHRITIS

Normal function of the wrist depends on pain-free motion and stability. Trauma and inflammatory conditions can disrupt the intrinsic ligaments of the wrist, resulting in instability and eventual degenerative changes (De Smet, 2002). Similarly, trauma and inflammation that directly affect the cartilage surfaces of the carpus can also result in degeneration. The proximal carpal row—consisting of the scaphoid, lunate, and triquetrum—function as a unit that allows radiocarpal articulation but also provides a concavity to support and allow motion of the distal carpal row. For the proximal row to work as a unit, the scapholunate and lunotriquetral ligaments must be intact.

Scapholunate Ligament

Flexion of the scaphoid with radial deviation of the hand is a normal motion of the proximal row that cannot be overcome by the examiner’s finger in the scaphoid tubercle (Beckenbaugh, 1984) (Figure 4-19). If it can be overcome, or if the scaphoid is ballotable, scapholunate ligament (SLL) laxity or tears are probable. The Watson test is performed by applying pressure on the flexed scaphoid tubercle while moving the hand back into ulnar deviation. Sudden and sharp dorsal wrist pain during this test indicates a significant SLL tear, resulting in instability and eventual osteoarthritis.

FIGURE 4-19 The scaphoid tubercle becomes more prominent (black arrows) as the scaphoid flexes and the wrist moves into radial deviation; the examiner can overcome this flexion only in cases of scapholunate ligament tear or laxity. A click and pain while returning to ulnar deviation is a positive Watson test and correlates to a scapholunate ligament tear.

Midcarpal Instability

This instability is characterized by vague, fatigue-like aching pain or a painful clunk with certain positions and is tested by stabilizing the radius with one hand and volarly translocating the carpus by pushing down on the hamate or capitate on the dorsum of the wrist (Figure 4-20). The wrist is reduced by bringing it into ulnar deviation, resulting in the “catch-up clunk” (Lichtman, 1984). Subluxation of the wrist is present in virtually everyone, but tenderness, pain, or reproduction of symptoms is important in the diagnosis of this type of instability.

FIGURE 4-20 THE MIDCARPAL CLUNK TEST.

Performed by stabilizing the radius (white bars) and translocating the wrist volarly (white arrow) while applying axial load (black arrow). Most wrists will sublux through the midcarpal joint with this maneuver (red arrow); a positive test is subluxation with reproduction of the patient’s pain.

TENDONS AT THE WRIST

The 24 tendons around the wrist are examined by their predictable location. Tendon inflammation occurs in certain age groups and with excessive use. Crepitus and swelling are noted with acute inflammation but are less common with the chronic pain that can plague the tendons. All tendons are tested while assessing for pain by stretching the tendon, palpating it, and testing it against resistance.

The first of six dorsal extensor compartments is at the radial styloid region of the wrist and contains the abductor pollicis longus and extensor pollicis brevis tendons. Inflammation here, known as de Quervain tenosynovitis, is assessed with the Finkelstein test (Finkelstein, 1930 and Field, 1979), in which the thumb is held in the palm by the patient’s flexed fingers as the wrist is passively brought into ulnar deviation. The maneuver reproduces the pain over the distal radius and the radial side of the wrist.

Inflammation of the extensor carpi radialis longus (ECRL) and brevis (ECRB) can occur in individuals who perform repetitive extension of the wrist, such as rowers. Pain is located at the junction where the two tendons emerge from under the muscles of the first compartment, approximately 3 cm proximal to the Lister tubercle on the dorsum of the distal radius (Wood, 1973). Inflammation here is known as intersection syndrome. The ECRL, and less commonly the ECRB, can also become inflamed at their insertion sites at the bases of the second and third metacarpals, respectively.

The extensor pollicis longus of the third compartment becomes inflamed at the Lister tubercle following minimally displaced distal radius fractures. In such cases, the tendon can quickly rupture, leading to a loss of extension of the IP joint of the thumb. The region can also become inflamed de novo, a condition known as Drummer boy’s palsy.

Inflammation of the extensor digitorum communis and extensor indicis proprius of the fourth compartment occurs most commonly with inflammatory arthritis. This is a frequent finding in rheumatoid arthritis (RA). Inflammation of the extensor digiti minimi of the fifth compartment is rare but can occur with arthritis from the DRUJ, which is directly beneath the compartment. In RA, rupture of the extensor tendons for the fingers at the wrist results in loss of active extension at the MCP joint (finger drop).

The sixth compartment contains the extensor carpi ulnaris. The most common malady affecting this tendon is subluxation, tested by manually attempting to sublux the tendon out of its groove between the ulnar head and ulnar styloid.

Both of the two wrist flexors can become symptomatic with repetitive or excessive flexion. The flexor carpi radialis (FCR) typically becomes inflamed on the ulnar side of the scaphoid tubercle, where it travels down and into a tunnel at the trapezial ridge. The flexor carpi ulnaris (FCU) typically becomes inflamed proximal to the pisiform.

Inflammation of the nine flexor tendons of the digits (FDS, FDP, and FPL) usually occurs proximal to the wrist creases on the anterior aspect of the distal forearm. It is usually boggy in nature and is worse with finger motion.

NERVES AT THE WRIST

The three major nerves at the wrist are assessed by percussion and compression and by assessing the appearance and power of the muscles that they innervate. The median nerve is percussed proximal to the flexor retinaculum, just radial to the palmaris longus tendon at the distal wrist crease. With symptomatic compression of the nerve in carpal tunnel syndrome, percussion produces paresthesia in the distribution of the nerve (Tinel sign) in the thumb, index, and middle fingers and the radial half of the ring finger. Sustained flexion of the wrist for 60 seconds can also induce finger paresthesias (Phalen wrist flexion sign). If the wrist cannot be flexed because of arthritis, pressure over the median nerve for 60 seconds often produces the same effect. The median nerve function is also assessed by gauging muscle atrophy and power of the thenar eminence (Palumbo, 2002).

Ulnar nerve entrapment at the Guyon canal can be assessed by compressing the ulnar nerve just radial to the pisiform for 1 minute. This produces numbness and tingling in the distribution of the ulnar nerve (positive ulnar nerve compression test). The Tinel sign will also be positive in the same distribution with percussion of the nerve. Prior to the wrist crease, the ulnar nerve gives off a sensory branch to the dorsal aspect of the hand. As such, sensory changes on the dorsum of the hand indicate more proximal compression of the nerve. Wasting may be noted in the intrinsic musculature of the hand as well as in the hypothenar eminence, depending on the site of compression. This may result in slight “clawing” of the little and ring fingers (hyperextension of MCP and flexion of PIP and DIP joints).

The superficial sensory branch of the radial nerve emerges from under the brachioradialis to innervate the dorsum of the radial two-thirds of the hand. Wartenberg neuritis of the nerve is assessed by percussion of the nerve in the region of the first compartment and radial styloid region. Neuritis can result from direct pressure or trauma, including a tight cast or splint, tight jewelry, or handcuffs.

ARTERIES AT THE WRIST

In vascular disorders of the hand, the patency of the radial and ulnar arteries can be assessed using the Allen test: The patient elevates the hand and makes a fist while the examiner occludes both the radial and the ulnar arteries at the wrist. The patient then extends the fingers and repeats the maneuver until blanching of the hand is seen. Each artery is then released, and the color of the hand returns to normal. If either artery is occluded, the hand remains blanched when this artery alone is released. A marked difference between the left and right hand, or sluggish refill longer than 20 seconds, may indicate artery inflammation (Buerger disease) or traumatic thrombosis of the ulnar artery (hypothenar hammer syndrome).

INTRODUCTION

It is important to be aware of possible complications from steroid injections into tendons or joints. The risk of septic arthritis from intraarticular aspiration or injection is small, but common sense and aseptic technique must be adhered to within reason. The physician should wear gloves for his or her own protection, as body fluids from the patient can carry viral disease through small fissures or cuts into the caregiver. Where there is concern about overlying skin infection, such as cellulitis or septic bursitis, it is best to defer putting a needle into the joint.

With respect to the hand and wrist, some joints are very small, and a large volume of fluid injected into the articular cavity can stretch the capsule, even to the point of capsular herniation or rupture. Some joints (IP, wrist) and tendon sheaths are very difficult to aspirate, and the procedure is better done under ultrasound.

Repeated cortisone injections into the same site with great frequency may contribute to thinning of the articular cartilage, articular laxity, or tendon rupture due to protein catabolism, although reports of such complications are only anecdotal. Although very safe, it is important to understand that cortisone injections should not be the mainstay of management for ongoing disease. They can alleviate acute pain and inflammation, but when problems are ongoing, chronic, or frequently recurrent, other management strategies should be considered.

Finally, the patient should be forewarned that when an injection is placed close to the skin, such as at the wrist or PIP joint, the overlying skin may become atrophic or hypopigmented for many months, even as long as a year.

With the hand and wrist, after an articular injection is complete, the patient should be advised to keep the area clean and dry for 24 hours to avoid infection. Pain after injection occurs most often with tissue infiltration, such as for de Quervain syndrome. Along with analgesic tablets, ice in a plastic bag, applied on and off every 30 seconds, can provide relief. Where local anesthetic is infiltrated near a nerve (e.g., carpal tunnel syndrome), patients should be apprised of the possibility of paresthesia for a couple of hours afterward (Fam, 1995).

Interphalangeal Joints

These joints are injected using a 25 gauge, 5/8 inch needle and a 1 mL syringe. Draw up 0.1 mL of local steroid and 0.1 mL of local anesthetic. The volume of injection should not exceed 0.3 mL to avoid stretching and damage of the capsule. Cadaveric studies have indicated that without ultrasound guidance, the needle is intraarticular in only 56% of cases; so if aspiration is important for diagnosis, ultrasound should be used (Raza et al, 2003). With the patient recumbent, the hand is placed palm down, fingers extended, on the examining table. For steroid injection the needle should be placed into the dorsomedial or dorsolateral aspect of the joint until the tip touches the articular cartilage. A slow injection is associated with slight ballooning of the capsule (Figure 4-21).

FIGURE 4-21 INJECTION INTO PROXIMAL INTERPHALANGEAL JOINT OF THE FINGER.

The needle is placed just radial or ulnar to the extensor tendon and inserted into the joint margin.

Metacarpophalangeal Joints

MCP joints are injected using a 25 gauge, 5/8 inch needle and 1 mL syringe. Draw up 0.2 mL of local steroid and 0.1 mL of local anesthetic. The volume of the injection should not exceed 0.4 mL to avoid stretching and damage of the capsule. The needle should be placed into the dorsomedial or dorsolateral aspect of the extended joint. As with the interphalangeal joint, it is often difficult to enter the intraarticular joint space. As the joint is injected, inflation of the capsule is palpable (Figure 4-22).

FIGURE 4-22 INJECTION INTO METACARPOPHALANGEAL (MCP) JOINT.

Similar to PIP injection, the needle is inserted beside the extensor tendon as far as the joint margin.

Wrist Joint

The radiocarpal joint is best approached from the dorsum of the wrist. The patient is supine with the hand prone on the examining table. A 22 gauge, 1 or 1½ inch needle is used. Local anesthetic can be infiltrated as the needle is inserted. The landmark is the Lister tubercle at the distal end of the radius. About 1 cm distal to the turbercle is a soft spot that represents the space between the distal radius and the base of the scaphoid. The needle is inserted vertical to the wrist to a depth of 2 cm. If resistance is met, pull back halfway and direct a bit in a distal and radial direction. With the needle in place, the syringe is exchanged (sometimes a needle clamp is needed) for one with local steroid to a volume of 1 mL (Figure 4-23).

FIGURE 4-23 INJECTION INTO WRIST USING LISTER TUBERCLE AS A LANDMARK (BLACK LINE).

Injection is placed 1 cm distal to this into the soft spot of the radioscaphoid joint.

Flexor Tendon (Saldana, 2001)

The patient is positioned recumbent, lying on the side to be injected, with the arm extended on the examining table and the hand held in a flat supine position. A 25 gauge, 5/8 inch needle can be used with a 1 mL syringe. The volume for injection should be about 0.6 mL. It may be helpful to mix 0.2 mL of local anesthetic with 0.4 mL of the injectable steroid.

The tendon to be injected is grasped between the thumb and forefinger of the examiner’s free hand, about 1 cm proximal to the distal palmar crease. The needle is inserted vertical to the palm, aimed in a slightly distal direction. Initially the needle tip may be in the substance of the tendon, so resistance may be encountered. The examiner should withdraw the needle until the steroid flows smoothly and easily. The tendon sheath will balloon in a tubular fashion as the steroid is injected (Figure 4-24).

FIGURE 4-24 INJECTION INTO FLEXOR TENDON OF FINGER.

Note: the injection can also be given starting in the palm, just proximal to the distal palmar crease, and aiming distally toward the finger.

de Quervain Syndrome

The first of six dorsal extensor compartments is at the radial styloid region of the wrist and contains the abductor pollicis longus and extensor pollicis brevis tendons. These tendons are held in place by a vaginal sheath. Inflammation here is known as de Quervain syndrome (Figure 4-25A). Injection is placed into the sheath with a 25 gauge, 5/8 inch needle. A 3 mL Luer lock syringe is filled with 0.5 mL of local steroid and 0.5 mL of local anesthetic. With the wrist in ulnar deviation, the needle is inserted on the radial aspect of the wrist at the radial styloid, about 3 cm proximal to the base of the first metacarpal. The needle is inserted in a slightly proximal direction, aiming toward the elbow, until resistance is met; the needle tip is pulled back slightly until the solution can be injected with little resistance. The sheath should swell slightly with the injection (see Figure 4-25B).

FIGURE 4-25 A, de QUERVAIN TENOSYNOVITIS OF THE WRISTS. B, INJECTION INTO FIRST COMPARTMENT SHEATH FOR ABDUCTOR POLLICIS LONGUS AND EXTENSOR POLLICIS BREVIS.

Line marks margin of radial styloid.

(From Hochberg H, Silman AJ, Smolen JS, et al., eds.: Rheumatology, 3rd ed. London: Mosby, 2003.)

Carpal Tunnel Syndrome

Injection into the carpal tunnel may relieve compression of the median nerve only temporarily. The palmaris longus tendon insertion is identified at the proximal palmar crease with resisted flexion of the third finger. A 22 gauge, 1 to 1½ inch needle is used with a 3 mL syringe. One mL of local steroid and a half mL of local anesthetic can be used. The needle is inserted just ulnar to the palmaris longus, at the proximal palmar crease, at a 20° to 30° angle to the skin, aimed toward the fourth finger (Figure 4-26). Snagging on a flexor tendon can occur, at which point the needle should be withdrawn slightly and reangled. The needle should be inserted to 2 cm. The anesthetic may leave some tingling in the median nerve distribution for a couple of hours.

FIGURE 4-26 INJECTION INTO CARPAL TUNNEL.

Note needle placement on ulnar side of palmaris longus as marked (black line).

First Carpometacarpal Joint

The base of the first metacarpal is identified at the distal end of the anatomical snuffbox between the abductor pollicis longus and the extensor pollicis brevis (EPB) tendons. Flexion of the thumb across the palm makes the joint easier to identify. A 1 mL syringe with a 25 gauge, 5/8 inch needle can be used. About 0.3 mL of local steroid should be mixed with 0.1 mL of local anesthetic. The needle is inserted perpendicular to the skin close to the EPB tendon to avoid the radial artery. Traction on the thumb can sometimes open up the joint space for better access (Figure 4-27).

FIGURE 4-27 INJECTION INTO CARPOMETACARPAL JOINT OF THUMB.

Lines mark base of proximal phalanx, abductor pollicis longus, and extensor carpi radialis tendons.